Columbia Encyclopedia

(Encyclopedia) heart, artificial, external or surgically implanted mechanical device designed to replace a patient's diseased heart. The first one used on a human being, the Jarvik-7, was implanted (1982) in Barney ...

(Encyclopedia) blood clotting, process by which the blood coagulates to form solid masses, or clots. In minor injuries, small oval bodies called platelets, or thrombocytes, tend to collect and form plugs in blood ve...

(Encyclopedia)  CE5 A. Cross section of the earth, showing its shells B. Detailed cross section of the crust and upper mantle: The lithosphere consists of the hard rock in the crust and upper mantle, lying above t...

(Encyclopedia) integrated circuit (IC), electronic circuit built on a semiconductor substrate, usually one of single-crystal silicon. The circuit, often called a chip, is packaged in a hermetically sealed case or a ...

(Encyclopedia) Canadian Alliance, former Canadian political party that had its origins in the Reform party of Canada, which was founded in 1987 in Winnipeg, Man., as a W Canada–based conservative alternative to th...

(Encyclopedia) Rhine Province, Ger. Rheinprovinz, former province of Prussia, W Germany. The province was also known as Rhenish Prussia and as the Rhineland. The northern section of the former province (which contai...

(Encyclopedia)  CE5 Formation of sperm cells through meiosis meiosis mīŏˈsĭs [key], process of nuclear division in a living cell by which the number of chromosomes is reduced to half the original number. Meio...

(Encyclopedia) Rh factor, protein substance present in the red blood cells of most people, capable of inducing intense antigenic reactions. The Rh, or rhesus, factor was discovered in 1940 by K. Landsteiner and A. S...

(Encyclopedia) Muslim League, political organization of India and Pakistan, founded 1906 as the All-India Muslim League by Aga Khan III. Its original purpose was to safeguard the political rights of Muslims in India...

(Encyclopedia)  CE5 Van Allen radiation belts: The solar wind, a stream of protons, electrons, and ions coming from the sun, gives the belts their asymmetrical shape. Van Allen radiation belts, belts of radiation...